The invention is particularly adaptable for use in pulse combustion apparatus, although not limited thereto. Typically, pulse combustion apparatus includes a combustion chamber and an exhaust line which may form a resonant system with the combustion chamber. The apparatus operates on a cycle in which a fuel charge is injected into the combustion chamber and ignited, and the charge then expands into the exhaust pipe, causing a partial vacuum in the combustion chamber which both assists in drawing in a fresh fuel charge and causes high temperature gas to be drawn back into the combustion chamber from the exhaust pipe to ignite the fresh fuel. The fresh fuel charge is ignited spontaneously from flame fronts in the returning high temperature gas, thereby establishing the next cycle. The apparatus is self-sustaining in combustion after initial ignition. The exhaust line is utilized as a heat exchanger to heat another medium, such as water or air.
The present invention is concerned with an ignition system for a boiler in which a series of ignition pulses may be generated in given time intervals between combustion chamber purge periods to ignite the fuel in the combustion chamber. If ignition does not occur after a predetermined number of cycles, the ignition system is shut down.
The present system is solid state in design, thus obviating wear on the gearing, contacts, etc. of electro-mechanical timers and provides an ignition system for a combustion chamber which is simple in construction and long in life.